1. Field of the Invention
The invention discloses novel alkoxylated salicylate esters of silicone compounds which contain an ester linkage, a polyoxyalkylene portion and a silicone polymer portion in the same molecule. Compounds of the invention are made by reacting (a) an alkoxylated carboxy silicone, and (b) salicylic acid to form an ester. Compounds of the invention by virtue of (i) the silicone group, (ii) the ester group and (iii) the ultra violet absorbing group salicylic, the compounds are effective durable ultra violet absorbers. The presence of the polyoxyalkylene portion of the molecule allows for the modification of the solubilities of the molecule in a variety of polar and non-polar solvents.
The reaction used to prepare the compounds of the present invention is an esterification of a carboxy silicone and salicylic acid. The resulting ester provides ultra violet absorbance and is durable to substrates like textile fabrics, hair and skin.
2. Arts and Practices
Silicone compounds have been known to be active at the surface of plastic, cellulosic and synthetic fibers as well as paper. They are good nondurable lubricants and are very stable to oxidation, however, their high cost and lack of efficiency at low concentrations as well as low durability have made their acceptance in commercial products quite low. In all instances, commercially available quaternaries are the active ingredient in traditional laundry care markets, with little or no silicone added.
The low efficiency and low durability of dimethylpolysiloxane is due to the fact that it is very water insoluble and deposits on the surface to obtain a minimum free energy in the solution. Simply, the silicone oil delivery to the surface by hydrophobic binding, not chemical bonding. At the surface, the dimethylpolysiloxane is a very effective fiber lubricant, however, there are two drawbacks, first; the dimethylpolysiloxane is not chemically bonded so the effect is very transient and disappears with one washing, and second; since there is no reaction of the dimethylpolysiloxane to the surface an equilibrium between fiber absorbed dimethylpolysiloxane and dimethylpolysiloxane in the dispersion results in very inefficient percentage of silicone deposited. A large amount of the expensive silicone goes down the drain with the waste water. The presence of the polyoxyalkylene portion of the molecule allows for the modification of the solubilities of the molecule in a variety of polar and non-polar solvents.
Silicone oils do not provide ultra violet absorption, and consequently protection from the damaging effects of the sun. The aromatic compounds that provide this type of absorbance are not durable to the surfaces of substrates.
Silicone carboxy compounds have been described in U.S. Pat. No. 5,296,625 to O'Lenick, incorporated herein by reference.